Doesn't properly detect python depends in .pyi files (cython)
Issue can be reproduced with [python-av](https://aur.archlinux.org/packages/python-av) package as of 14.1.0-1, I didn't check any repo packages for that. There are 180 with .pyi files as of writing this post.
Namcap doesn't detect 2 dependencies:
```
python-av W: Dependency included, but may not be needed ('python-numpy')
python-av W: Dependency included, but may not be needed ('python-pillow')
```
These are imported in `.pyi` files
```
usr/lib/python3.13/site-packages/av/sidedata/motionvectors.pyi:import numpy as np
usr/lib/python3.13/site-packages/av/audio/frame.pyi:import numpy as np
usr/lib/python3.13/site-packages/av/video/frame.pyi:import numpy as np
usr/lib/python3.13/site-packages/av/video/frame.pyi:from PIL import Image
```
and trying to run [demo from homepage](https://pyav.basswood-io.com/docs/stable/#basic-demo) results in an error:
```
Traceback (most recent call last):
File "<python-input-8>", line 2, in <module>
frame.to_image().save(f"frame-{index:04d}.jpg")
~~~~~~~~~~~~~~^^
File "av/video/frame.pyx", line 266, in av.video.frame.VideoFrame.to_image
ModuleNotFoundError: No module named 'PIL'
```
issue